Just a heads up - blister mites have been spotted recently
on pear. It appears the mites are moving into the new growth
of the trees now from older infested leaves. People might
want to monitor their pears for activity as the hot dry weather
we have had this year will favor build up of these eriophyid
 mites. These mites can be found out on the leaf at this time but
they also can hide out within the blistered tissue. Those
managing the mites with contact sprays, such as with horticultural
 oil, may need to make more than one application.
More information at link below:
http://oregonstate.edu/dept/nurspest/pear_leaf_blister_mite.htm